Patent application title: Organic light emitting device

Abstract:

An organic light emitting device includes a substrate having a plurality
of pixels, each pixel comprising a plurality of sub-pixels. Each
sub-pixel includes an emission area that has a first electrode, a second
electrode and an emitting layer, with the emitting layer of at least one
sub-pixel includes a phosphorescence material. In addition to these
features, the device includes a scan line to provide scan signal to a
corresponding sub-pixel, a data line configured to supply data signal to
a corresponding sub-pixel, and a power supply line to provide power to a
corresponding sub-pixel. The data line and power supply line have a
single-layer structure, and a taper angle of each of the data line and
the power supply line lies in a predetermined range.

Claims:

1. An organic light emitting device comprising:a substrate having a
plurality of pixels, each pixel comprising a plurality of sub-pixels,
wherein each sub-pixel includes an emission area, the emission area
including a first electrode, a second electrode and an emitting layer;a
plurality of scan lines, a scan line configured to provide scan signal to
a corresponding sub-pixel;a plurality of data lines, a data line
configured to supply data signal to a corresponding sub-pixel;a plurality
of power supply lines, a power supply line configured to provide power to
a corresponding sub-pixel, wherein the data line and the power supply
line have a single-layer structure and wherein a taper angle of each of
the data line and the power supply line lies substantially in a range
between 40.degree. to 70.degree..

2. The organic light emitting device of claim 1, wherein a taper angle of
each of the data line and the scan line lies substantially in a range
between 50.degree. and 60.degree..

3. The organic light emitting device of claim 1, wherein a resistance of
the data line is lower than a resistance of the scan line.

4. The organic light emitting device of claim 1, wherein a thickness of
the data line is larger than a thickness of the scan line.

5. The organic light emitting device of claim 1, wherein a width of the
data line is larger than a width of the scan line.

6. The organic light emitting device of claim 1, wherein a resistance of
the power supply line is lower than a resistance of the scan line.

7. The organic light emitting device of claim 1, wherein a resistance of
the power supply line is lower than a resistance of the data line.

8. The organic light emitting device of claim 1, wherein a width of the
power supply line is larger than a width of the data line.

9. The organic light emitting device of claim 1, wherein a cross-sectional
area of the data line is larger than a cross-sectional area of the scan
line.

10. The organic light emitting device of claim 1, wherein a
cross-sectional area of the power supply line is larger than a
cross-sectional area of the data line.

11. An organic light emitting device comprising:a substrate having a
plurality of pixels, each pixel comprising a plurality of sub-pixels,
wherein each sub-pixel includes an emission area, the emission area
including a first electrode, a second electrode and an emitting layer;a
plurality of scan lines, a scan line configured to provide scan signal to
a corresponding sub-pixel;a plurality of data lines, a data line
configured to supply data signal to a corresponding sub-pixel;a plurality
of power supply lines, a power supply line configured to provide power to
a corresponding sub-pixel, wherein a taper angle of each of the data line
and the power supply line lies substantially in a range between
40.degree. to 70.degree., wherein the data line and the power supply line
have a single-layer structure, and wherein the data line or the power
supply line are formed from any one selected from the group consisting of
molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti),
nickel (Ni), neodymium (Nd), and copper (Cu).

12. An organic light emitting device comprising:a substrate having a
plurality of pixels, each pixel comprising a plurality of sub-pixels,
wherein each sub-pixel includes an emission area, the emission area
including a first electrode, a second electrode and an emitting layer;a
plurality of scan lines, a scan line configured to provide scan signal to
a corresponding sub-pixel;a plurality of data lines, a data line
configured to supply data signal to a corresponding sub-pixel;a plurality
of power supply lines, a power supply line configured to provide power to
a corresponding sub-pixel, wherein a taper angle of each of the data line
and the power supply line lies substantially in a range between
40.degree. to 70.degree., wherein the data line and the power supply line
have a single-layer structure, and wherein the emitting layer of at least
one sub-pixel includes a phosphorescence material.

13. An organic light emitting device comprising:a substrate having a
plurality of pixels, each pixel comprising a plurality of sub-pixels,
wherein each sub-pixel includes an emission area, the emission area
including a first electrode, a second electrode and an emitting layer;a
plurality of scan lines, a scan line configured to provide scan signal to
a corresponding sub-pixel;a plurality of data lines, a data line
configured to supply data signal to a corresponding sub-pixel;a plurality
of power supply lines, a power supply line configured to provide power to
a corresponding sub-pixel, wherein each of the data line and power supply
line has a triple-layer structure and wherein a taper angle of a first
layer lies substantially between 30.degree. to 60.degree., a taper angle
of a second layer lies substantially between 40.degree. to 70.degree.,
and a taper angle of a third layer lies substantially between 70.degree.
to 90.degree..

14. The organic light emitting device of claim 13 wherein the triple-layer
structure includes Mo/Al/Mo or Mo/Al--Nd/Mo or Ti/Al/Ti.

15. An organic light emitting device comprising:a substrate having a
plurality of pixels, each pixel comprising a plurality of sub-pixels,
wherein each sub-pixel includes an emission area, the emission area
including a first electrode, a second electrode and an emitting layer;a
plurality of scan lines, a scan line configured to provide scan signal to
a corresponding sub-pixel;a plurality of data lines, a data line
configured to supply data signal to a corresponding sub-pixel;a plurality
of power supply lines, a power supply line configured to provide power to
a corresponding sub-pixel, wherein each of the data line and power supply
line has a triple-layer structure and wherein a taper angle of a first
layer lies substantially between 30.degree. to 60.degree., a taper angle
of a second layer lies substantially between 40.degree. to 70.degree.,
and a taper angle of a third layer lies substantially between 70.degree.
to 90.degree., andwherein each layer of the data line or power supply
line is formed from one of the group consisting of molybdenum (Mo),
aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni),
neodymium (Nd), and copper (Cu).

16. The device of claim 15, all the layers of the data line or the power
supply line are made from a same material selected from the group.

17. An organic light emitting device comprising:a substrate having a
plurality of pixels, each pixel comprising a plurality of sub-pixels,
wherein each sub-pixel includes an emission area, the emission area
including a first electrode, a second electrode and an emitting layer;a
plurality of scan lines, a scan line configured to provide scan signal to
a corresponding sub-pixel;a plurality of data lines, a data line
configured to supply data signal to a corresponding sub-pixel;a plurality
of power supply lines, a power supply line configured to provide power to
a corresponding sub-pixel, wherein each of the data line and power supply
line has a triple-layer structure and wherein a taper angle of a first
layer lies substantially between 30.degree. to 60.degree., a taper angle
of a second layer lies substantially between 40.degree. to 70.degree.,
and a taper angle of a third layer lies substantially between 70.degree.
to 90.degree., and wherein the emitting layer of at least one sub-pixel
includes a phosphorescence material.

[0003]One or more embodiments described herein relate to a display device.

[0004]2. Background

[0005]The importance of flat panel displays has recently increased with
consumer demand for multimedia products and services. An organic light
emitting device (OLED) is desirable because it has a rapid response time,
low power consumption, self-emission structure, and wide viewing angle.
In spite of their many advantages, OLEDs tend to have non-uniform
luminance characteristics which degrade reliability.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006]FIG. 1 is a view of one embodiment of an organic light emitting
device.

[0007]FIG. 2 is a cross-sectional view taken along a line I-I' of FIG. 1.

[0008]FIGS. 3 and 4 are cross-sectional views of enlarged area A in FIG.
2.

[0009]FIGS. 5A to 5C illustrate various implementations of a color image
display method in an organic light emitting device according to an
exemplary embodiment of the present invention.

DETAILED DESCRIPTION

[0010]Organic light emitting devices may be classified as passive matrix
or active matrix devices. In a passive matrix device, anode electrodes
are oriented at right angles to cathode electrodes, and the device is
driven by a line-selection scheme. In an active matrix device, a
thin-film transistor is connected to each pixel (or sub-pixel) electrode
and the device is driven based on the capacitance of a capacitor
connected to a gate electrode of the thin film transistor.

[0011]Also, in active matrix device, scan and data signals are supplied to
sub-pixels through corresponding scan and data lines, and light is
emitted based on electrical power supplied to the sub-pixels through one
or more power supply lines. However, because the scan, data, and power
supply lines are made of a metal, signals supplied to a sub-pixel far
away from a supply source may be distorted compared to signals supplied
to a sub-pixel bear the supply source. This effect is caused, at least in
part, by the resistance associated with the lines. As a result, luminance
of the organic light emitting device is not uniform, which adversely
affects reliability.

[0012]As described herein, an organic light emitting device may be
provided to include a substrate having a plurality of pixels, each pixel
comprising a plurality of sub-pixels. FIG. 1 shows a structure of one
embodiment of a sub-pixel of the organic light emitting device. This
structure includes a substrate 100 having a sub-pixel area and a
non-sub-pixel area. The sub-pixel area is defined by a scan line 120a
positioned in one direction, a data line 140a positioned perpendicular to
the scan line, and a power supply line 140e parallel to the data line.
The scan line, data line, and power supply line are positioned in the
non-sub-pixel area.

[0013]The sub-pixel area includes a switching thin film transistor T1
connected to scan line 120a and data line 140a, a capacitor Cst connected
to the switching thin film transistor T1 and the power supply line 140e,
and a driving thin film transistor T2 connected to the capacitor Cst and
the power supply line. The capacitor Cst may include a capacitor lower
electrode 120b and a capacitor upper electrode 140a.

[0014]An organic light emitting diode is also positioned in the sub-pixel
area. The organic light emitting diode includes a first electrode 155
electrically connected to the driving thin film transistor T2, an
emitting layer (not shown) positioned on the first electrode 155, and a
second electrode (not shown).

[0015]FIG. 2 is a cross-sectional view taken along a line I-I' of FIG. 1.
As shown, a buffer layer 105 is positioned on the substrate and serves to
protect a thin film transistor from impurities (such as alkali ions)
discharged from the substrate during a subsequent process. The buffer
layer may be selectively formed using silicon oxide (SiO2) or
silicon nitride (SiNX), and the substrate may be formed of glass,
plastic, or metal.

[0016]A semiconductor layer 110 is positioned on the buffer layer and may
be formed from amorphous silicon or crystallized poly-silicon. The
semiconductor layer may include a source area and a drain area having
p-type or n-type impurities, as well as a channel area.

[0017]A first insulating layer 115, which may be a gate insulating layer,
is positioned on the semiconductor layer. The first insulating layer may
be made of a silicon oxide (SiO2) layer or a silicon nitride
(SiNX) layer, or may have a multi-layered structure formed from a
combination thereof.

[0018]A gate electrode 120c is positioned on the first insulating layer
115 in a given area of the semiconductor layer, e.g., in a location
corresponding to the channel area of the semiconductor layer where
impurities are doped. The scan line 120a and capacitor lower electrode
120b may be positioned on the same formation layer as the gate electrode.

[0019]The gate electrode 120c may be made of any one of molybdenum (Mo),
aluminum (Al), chromium (Cr), gold (Au), titanium (Ii), nickel (Ni),
neodymium (Nd), or copper (Cu) or a combination thereof. The gate
electrode may have a multi-layered structure made of Mo, Al, Cr, Au, Ti,
Ni, Nd, or Cu, or a combination thereof, or a double-layer structure
made, for example, of Mo/Al--Nd.

[0020]The scan line 120a may be made of Mo, Al, Cr, Au, Ti, Ni, Nd, or Cu,
or a combination thereof. According to one embodiment, the scan line may
have a multi-layered structure made of Mo, Al, Cr, Au, Ti, Ni, Nd, or Cu
or a combination thereof. According to another embodiment, the scan line
has a double-layer structure made, for example, of Mo/Al--Nd.

[0021]The scan line 120a has a predetermined width, for example, equal to
or more than 3 μm and less than 5 μm and a predetermined thickness,
for example, equal to or more than 300 nm and less than 450 nm. In
operation, the scan line supplies a scan signal to one or more
sub-pixels; that is, a scan driver positioned outside the sub-pixel area
supplies scan signals to one or more sub-pixels through scan line 120a.

[0022]Because the scan line is a metal conductive line which has
associated resistance characteristics, a value of a scan signal supplied
to a sub-pixel near the scan driver may be different from a value of a
scan signal supplied to a sub-pixel far away from the driver. More
specifically, since the scan driver supplies a scan signal to sub-pixels
through scan line 120a, the scan signal of each sub-pixel may have a
different value due to a resistance associated with the scan line. As a
result, voltage drop (IR-drop) may be caused by the resistance of the
line. According to one embodiment, the thickness and/or width of the scan
line is adjusted to set or control the resistance of the line, to thereby
prevent or reduce the effects of a voltage drop in the values of scan
signals applied to the sub-pixels connected to the line.

[0023]In one non-limiting case, scan line 120a may have a width equal to
or more than 3 μm and less than 5 μm and a thickness equal to or
more than 300 nm and less than 450 nm. When the width of the scan line is
equal to or more than 3 μm, the resistance of the scan line is reduced
or minimized and thus voltage drop in scan signal values can be prevented
in spite of how far away the pixels are from the scan driver. As a
result, non-uniformity in the luminance of the organic light emitting
device can be reduced or prevented. When the width of the scan line is
less than 5 μm, pixel shrinkage can be prevented due to an increase in
the width of the scan line.

[0024]When the thickness of the scan line is equal to or more than 300 nm,
the resistance of the scan line is reduced or minimized and thus voltage
drop in scan signal values can be prevented. As a result, non-uniformity
in luminance of the OLED can be prevented. And, when the thickness of the
scan line is less than 450 nm, step coverage of layers such as an
insulating layer to be formed later can be reduced. Hence, exposure of
the scan line can be prevented which will prevent or reduce the chances
of a short from occurring between the scan line and another conductive
line.

[0025]A second insulating layer 125, which may serve as an interlayer
dielectric, may be positioned on the substrate on which scan line 120a,
capacitor lower electrode 120b, and gate electrode 120c are positioned.
The second insulating layer may be made of silicon oxide (SiO2)
layer or a silicon nitride (SiNX) layer, or may be a multi-layered
structure that includes a combination of the aforementioned materials.

[0026]Contact holes 130b and 130c may be positioned inside second
insulating layer 125 and first insulating layer 115 to expose a portion
of semiconductor layer 120. A drain electrode 140c and source electrode
140d in the sub-pixel area are to be electrically connected to the
semiconductor layer through the contact holes, passing through the first
and second insulating layers.

[0027]The drain electrode 140c and source electrode 140d may have a
single-layered or multi-layered structure. If each of the drain and
source electrodes has a single-layered structure, the electrodes may be
made of Mo, Al, Cr, Au, Ti, Ni, Nd, or Cu, or a combination thereof. If
each of the drain and source electrodes have a multi-layered structure,
the electrodes may have a double-layer structure made of Mo/Al--Nd or a
triple-layer structure made of Mo/Al/Mo or Mo/Al--Nd/Mo.

[0028]The data line 140a, capacitor upper electrode 140b, and power supply
line 140e may be positioned on the same formation layer as drain
electrode 140c and source electrode 140d. The data line and power supply
line are positioned in the non-sub-pixel area and each may have a
single-layered structure or a multi-layered structure. If the data and
power supply lines each have a single-layered structure, the lines may be
made of Mo, Al, Cr, Au, Ti, Ni, Nd, or Cu or a combination thereof.

[0029]If the data and power supply lines each have a multi-layered
structure, the lines may have a double-layer structure made of Mo/Al--Nd
or a triple-layer structure made of Mo/Al/Mo or Mo/Al--Nd/Mo. If each of
the data and power supply lines has a triple-layer structure, the lines
may be made of Mo/Al--Nd/Mo.

[0030]The data line 140a may have a predetermined width, for example, in
the range of 3 to 5 μm and a predetermined thickness, for example, in
the range of 450 to 600 nm. A data driver positioned outside the
sub-pixel area supplies a data signal to one or more sub-pixels through
the data line.

[0031]Because data line 140a is a metal conductive line which has
associated resistance characteristics, a value of a data signal supplied
to a sub-pixel near the data driver may be different from a value of a
data signal supplied to a sub-pixel far away from the data driver. More
specifically, since the data driver supplies a data signal to one or
sub-pixels through the data line, the data signal supplied the sub-pixels
may have different values due to a resistance of the data line 140a. As a
result, voltage drop (IR-drop) may be caused by the resistance of the
data line. According to one embodiment, a thickness and/or width of the
data line is adjusted to set or control the resistance of the data line,
to thereby prevent or reduce the effects of a voltage drop in the values
of data signals applied to the sub-pixels connected to the line.

[0032]According to one embodiment, the data line may have a width, for
example, in the range of 3 to 5 μm and/or thickness, for example, in
the range of 450 to 600 nm. If the width of the data line is equal to or
more than 3 μm, the resistance of the data line is reduced or
minimized and thus the voltage drop can be prevented. If the width of the
data line is equal to or less than 5 μM, pixel shrinkage can be
prevented due to an increase in the width of the data line.

[0033]Also, when the thickness of the data line is, for example, equal to
or more than 450 nm, the resistance of the line is reduced or minimized
and thus voltage drop can be prevented. When the thickness of the data
line is, for example, equal to or less than 600 nm, step coverage of
layers such as an insulating layer to be formed later can also be
reduced. Hence, exposure of the data line can be prevented, thus
preventing or reducing the chances of a short from forming between the
data line and another conductive line.

[0034]The power supply line 140e may have a width, for example, in the
range of 5 to 7 μm and/or thickness of 450 to 600 nm. The power supply
line is used to supply electrical power to the sub-pixels connected to
the line.

[0035]Because the power supply line 140e is a metal conductive line with
associated resistance characteristics, electrical power supplied to a
sub-pixel near a power supply unit (not shown) may be different from
electrical power supplied to a sub-pixel far away from the power supply
unit. More specifically, since the power supply unit supplies electrical
power to each sub-pixel through the power supply line, the electrical
power supplied to sub-pixels connected to the line may have different
values due to a resistance of the line. As a result, a voltage drop
(IR-drop) in electrical power values may be caused by the resistance of
the power supply line. According to one embodiment, a thickness and/or
width of the power supply line 140e is adjusted to set or control the
resistance of the line, to thereby prevent or reduce the effects of a
voltage drop in power values applied to the sub-pixels connected to the
line.

[0036]According to one embodiment, the power supply line has a
predetermined width, for example, in a range of 5 to 7 μm and/or a
predetermined thickness, for example, in a range of 450 to 600 nm. In the
foregoing example, if the width of the power supply line is equal to or
more than 5 μm, the resistance of the line is reduced or minimized and
thus non-uniformity in luminance caused by a voltage drop in the line can
be reduced or prevented. If the width of the power supply line is equal
to or less than 7 μm, sub-pixel shrinkage can also be prevented due to
an increase in the width of the power supply line.

[0037]In the foregoing example, if the thickness of the power supply line
is equal to or more than 450 nm, the resistance of the line is reduced or
minimized and thus non-uniformity in luminance caused by the voltage drop
can be reduced or prevented. If the thickness of the power supply line is
equal to or less than 600 nm, step coverage of layers such as an
insulating layer to be formed later can be reduced. Hence, exposure of
the power supply line can be prevented, to thereby prevent or reduce the
chances of a short from occurring between the power supply line and
another conductive line.

[0038]According to another embodiment, data line 140a and power supply
line 140e may have a triple-layer structure including Mo/Al/Mo or
Mo/Al--Nd/Mo. With this structure, a thickness of a first layer may range
from 40 to 60 nm, a thickness of a second layer may range from 400 to 500
nm, and a thickness of a third layer may range from 10 to 30 nm.

[0039]In a triple-layer structure, a Mo layer forming the first layer may
serve as an ohmic contact to reduce resistance between the Mo layer and
another layer, and a thickness of the Mo layer may range from 40 to 60
nm. An Al or Al--Nd layer forming the second layer has low resistance and
may be used to reduce resistances of the line. A thickness of the Al or
Al--Nd layer may range from 400 to 500 nm. A Mo layer forming the third
layer may serve as a protective layer for avoiding a so-called Al or
Al--Nd hillock phenomenon, in which Al or Al--Nd rises to a high
temperature in a succeeding thermal process. A thickness of the Mo layer
may range from 10 to 30 nm.

[0040]FIGS. 3 and 4 are cross-sectional views of enlarged area A in FIG.
2. As shown in these views, the data line 140a and power supply line 140e
may have a single-layered structure or multi-layered structure. As
illustrated in FIG. 3, when each of the data line and power supply line
has a single-layered structure, a taper angle θ1 of each of the
data line 140a and the power supply line 140e may lie in range
substantially from 40° to 70°.

[0041]When taper angle θ1 is equal to or more than 40°, an
electric field concentrates in a peaked edge portion and thus damage to
an insulating layer covering the data line and power supply line can be
prevented. The taper angle θ1 of each of the data line and power
supply line may be equal to or more than 50° in one particular
embodiment.

[0042]When the taper angle θ1 is equal to or less than 70°,
step coverage of layers such as an insulating layer to be formed later
can be reduced. Hence, exposure of the data line 140a and power supply
line 140e can be prevented, and thus a short between the data or power
supply line and another conductive line can be prevented. The taper angle
θ1 of the data line and power supply line may be equal to or less
than 60° in one particular embodiment.

[0043]As illustrated in FIG. 4, alternatively, data line 140a and power
supply line 140e may have a multi-layered structure, for instance, a
triple-layer structure including Mo/Al--Nd/Mo. When the data line and
power supply line have a triple-layer structure, a taper angle O2 of
a first layer may range from 30° to 60°, a taper angle
θ3 of a second layer may range from 40° to 70°, and a
taper angle θ4 of a third layer may range from 70° to
90°.

[0044]Additionally, the resistances of the data and power supply lines are
reduced or minimized, and voltage drop of the values applied along the
length of the lines can be prevented due to a reduction in the
resistances of data and power supply lines. Hence, non-uniformity in
luminance can be prevented. Further, exposure of the data and power
supply lines can be prevented due to a reduction in step coverage of
layers such as an insulating layer to be formed later.

[0045]Thus, according to one embodiment, the width, thickness, and taper
angle of each line 120a, 140a and 140e can be adjusted to set, control,
or reduce resistances of the lines (including the data line 140a and the
power supply line 140e) to desired values. These resistances may be set
to be relative to one another.

[0046]For example, a resistance of data line 140a may be set to be lower
than a resistance of scan line 120a. More specifically, the thickness of
the data line may be greater than the thickness of the scan line, and the
width of the data line may be greater than the width of the scan line.
Hence, a cross-sectional area of data line 140a (determined by thickness
and width) may be larger than a cross-sectional area of scan line 120a.

[0047]More specifically, because a supply frequency of the data signal is
higher than a supply frequency of the scan signal, the data signal is
sensitive to line resistance. Hence, distortion of the data signal is
larger than the distortion of the scan signal. Accordingly, the
resistance of the data line can be set to be lower than the resistance of
the scan line, by setting the cross-sectional area of data line 140a to
be larger than the cross-sectional area of scan line 120a.

[0048]In accordance with another embodiment, a resistance of power supply
line 140e may be set to be lower than a resistance of data line 140a.
This may be accomplished, for example, by setting the width of the power
supply line may to be larger than the width of the data line. The
thickness or other cross-sectional dimensions may also be set. As a
result, a cross-sectional area of the power supply line (determined by
the width and/or thickness) may be larger than a cross-sectional area of
the data line. This may have the following effect.

[0049]While data line 140a sends data signals to sub-pixels, current does
not flow into the data line in a normal state. Therefore, influence of
voltage drop on the data line may be less than influence of voltage drop
on the power supply line. However, since the power supply line is
directly connected to the organic light emitting diode including the
first electrode 155, emitting layer, and second electrode, the voltage
drop of power supply line 140e directly affects non-uniformity of
luminance. Accordingly, the power supply line 140e is very sensitive to
the resistance.

[0050]Accordingly, the resistance of power supply line 140e may be set to
be lower than the resistance of data line 140a, by setting the
cross-sectional area of the power supply line to be larger than the
cross-sectional area of the data line.

[0051]In accordance with some embodiments, a third insulating layer 145
may be positioned on data line 140a, capacitor upper electrode 104b,
drain electrode 140c, source electrode 140d, and power supply line 140e.
The third insulating layer may, for example, be a planarization layer for
obviating the height difference of a lower structure. The third
insulating layer may be made of an organic material such as polyimide,
benzocyclobutene-based resin or acrylate or an inorganic material such as
spin on glass (SOG) obtained by spin-coating silicone oxide (SiO2)
in the liquid form and solidifying it. Otherwise, the third insulating
layer may be a passivation layer and may include a silicon oxide
(SiO2) layer, a silicon nitride (SiNX) layer, or a
multi-layered structure including a combination thereof.

[0052]A via hole 150 is positioned inside third insulating layer 145 to
expose one of the source or drain electrodes 140c and 140d. The first
electrode 155 is positioned on the third insulating layer to be
electrically connected to one of the source and drain electrodes 140c and
140d via the via hole 150.

[0053]The first electrode 155 may be an anode electrode and may be or
include a transparent electrode or a reflection electrode. When the
organic light emitting device has a bottom emission or dual emission
structure, the first electrode may be a transparent electrode made of
indium-tin-oxide (ITO), indium-zinc-oxide (IZO), or zinc oxide (ZnO).
When the organic light emitting device has a top emission structure, the
first electrode may be a reflection electrode made of Al, Ag, or Ni and
may be positioned under a layer formed of one of ITO, IZO, or ZnO. Also,
a reflection layer made of Al, Ag, or Ni may be positioned between two
layers formed of one of ITO, IZO, or ZnO.

[0054]A fourth insulating layer 160 including an opening 165 is positioned
on the first electrode. The opening may serve to provide electrical
insulation between neighboring first electrodes 155 and may expose a
portion of the first electrode. An emitting layer 175 is positioned on
the first electrode exposed by opening 165. The emitting layer may made
of a material capable of emitting red, green, or blue light and, for
example, may be formed using a phosphorescence material or a fluorescence
material.

[0055]In a case where emitting layer 175 emits red light, the emitting
layer includes a host material including carbazole biphenyl (CBP) or
1,3-bis(carbazol-9-yl (mCP), and may be formed of a phosphorescence
material including a dopant material including
PIQIr(acac)(bis(1-phenylisoquinoline)acetylacetonate iridium),
PQIr(acac)(bis(1-phenylquinoline)acetylacetonate iridium),
PQIr(tris(1-phenylquinoline)iridium), or PtOEP(octaethylporphyrin
platinum) or a fluorescence material including PBD:Eu(DBM)3(Phen) or
Perylene.

[0056]In the case where the emitting layer emits red light, a highest
occupied molecular orbital of the host material may range from 5.0 to
6.5, and a lowest unoccupied molecular orbital of the host material may
range from 2.0 to 3.5. A highest occupied molecular orbital of the dopant
material may range from 4.0 to 6.0, and a lowest unoccupied molecular
orbital of the dopant material may range from 2.4 to 3.5.

[0057]In the case where the emitting layer emits green light, the emitting
layer includes a host material including CBP or mCP, and may be formed of
a phosphorescence material including a dopant material including
Ir(ppy)3(fac tris(2-phenylpyridine)iridium) or a fluorescence material
including Alq3(tris(8-hydroxyquinolino)aluminum).

[0058]In the case where the emitting layer emits green light, a highest
occupied molecular orbital of the host material may range from 5.0 to
6.5, and a lowest unoccupied molecular orbital of the host material may
range from 2.0 to 3.5. A highest occupied molecular orbital of the dopant
material may range from 4.5 to 6.0, and a lowest unoccupied molecular
orbital of the dopant material may range from 2.0 to 3.5.

[0059]In the case where the emitting layer emits blue light, the emitting
layer includes a host material including CBP or mCP, and may be formed of
a phosphorescence material including a dopant material including (4,6-F2
ppy)2Irpic or a fluorescence material including spiro-DPVBi, spiro-6P,
distyryl-benzene (DSB), distyryl-arylene (DSA), PFO-based polymers,
PPV-based polymers, or a combination thereof.

[0060]In the case where the emitting layer emits blue light, a highest
occupied molecular orbital of the host material may range from 5.0 to
6.5, and a lowest unoccupied molecular orbital of the host material may
range from 2.0 to 3.5. A highest occupied molecular orbital of the dopant
material may range from 4.5 to 6.0, and a lowest unoccupied molecular
orbital of the dopant material may range from 2.0 to 3.5.

[0061]A second electrode 180 is positioned on or over emitting layer 175.
The second electrode may be a cathode electrode and may be made of Mg,
Ca, Al, or Ag having a low work function or a combination thereof. When
the organic light emitting device has a top emission or dual emission
structure, the second electrode may be thin to allow the second electrode
to transmit a certain amount of light. When the organic light emitting
device has a bottom emission structure, the second electrode may be thick
to allow the second electrode to reflect light.

[0062]As described above, an organic light emitting device according to
one or more embodiments can achieve uniform luminance by adjusting the
taper angle and/or the resistance of the data line and/or power supply
line and/or scan line relative to one another. As a result, reliability
of the organic light emitting device can be improved. The taper angles
may be formed using a wet (e.g., chemical etch) process or a dry (e.g.,
laser) etch process.

[0063]In one aspect, an organic light emitting device comprises a
substrate including a sub-pixel area and a non-sub-pixel area, a scan
line that is positioned in the non-sub-pixel area and supplies a scan
signal to the sub-pixel area, a data line that is positioned in the
non-sub-pixel area and supplies a data signal to the sub-pixel area, and
a power supply line that is positioned in the non-sub-pixel area and
supplies a power to the sub-pixel area, wherein a taper angle of each of
the data line and the scan line substantially ranges from 40° to
70°.

[0064]In another aspect, an organic light emitting device comprises a
substrate including a sub-pixel area and a non-sub-pixel area, a scan
line that is positioned in the non-sub-pixel area and supplies a scan
signal to the sub-pixel area, a data line that is positioned in the
non-sub-pixel area and supplies a data signal to the sub-pixel area and
has a triple-layer structure and a power supply line that is positioned
in the non-sub-pixel area and supplies a power to the sub-pixel area and
has a triple-layer structure. And in the triple-layer structure, a taper
angle of a first layer substantially ranges from 30° to
60°, a taper angle of a second layer substantially ranges from
40° to 70°, and a taper angle of a third layer
substantially ranges from 70° to 90° in the triple-layer
structure.

[0065]In still another aspect, an organic light emitting device comprises
a substrate including a non-sub-pixel area and a sub-pixel area which
includes a gate electrode, a gate insulating layer positioned on the gate
electrode, a semiconductor layer positioned on the gate insulating layer,
a source electrode and a drain electrode electrically connected to the
semiconductor layer, a first electrode electrically connected to the
drain electrode, an emitting layer positioned on the first electrode, and
a second electrode positioned on the emitting layer, a scan line that is
positioned in the non-sub-pixel area and supplies a scan signal to the
pixel area, a data line that is positioned in the non-sub-pixel area and
supplies a data signal to the sub-pixel area and a power supply line that
is positioned in the non-sub-pixel area and supplies a power to the
sub-pixel area. A taper angle of each of the data line and the power
supply line substantially ranges from 40° to 70°.

[0066]Additional embodiments relating to various color image display
methods in an organic light emitting device will now be described with
reference to FIGS. 5A to 5C.

[0067]FIGS. 5A to 5C illustrate various implementations of a color image
display method in an organic light emitting device according to one
exemplary embodiment.

[0069]The red, green and blue light produced by the red, green and blue
organic emitting layers 201R, 201G and 201B is mixed to display a color
image.

[0070]It may be understood in FIG. 5A that the red, green and blue organic
emitting layers 201R, 201G and 201B each include an electron transporting
layer, an emitting layer, a hole transporting layer, and the like. In
FIG. 5A, a reference numeral 203 indicates a cathode electrode, 205 an
anode electrode, and 210 a substrate. It is possible to variously change
a disposition and a configuration of the cathode electrode, the anode
electrode and the substrate.

[0076]It may be understood in FIG. 5c that the blue organic emitting layer
401B includes an electron transporting layer, an emitting layer, a hole
transporting layer, and the like

[0077]A difference between driving voltages, e.g., the power voltages VDD
and Vss of the organic light emitting device may change depending on the
size of the display panel 100 and a driving manner. A magnitude of the
driving voltage is shown in the following Tables 1 and 2. Table 1
indicates a driving voltage magnitude in case of a digital driving
manner, and Table 2 indicates a driving voltage magnitude in case of an
analog driving manner.

[0078]Any reference in this specification to "one embodiment," "an
embodiment," "example embodiment," etc., means that a particular feature,
structure, or characteristic described in connection with the embodiment
is included in at least one embodiment of the invention. The appearances
of such phrases in various places in the specification are not
necessarily all referring to the same embodiment. Further, when a
particular feature, structure, or characteristic is described in
connection with any embodiment, it is submitted that it is within the
purview of one skilled in the art to effect such feature, structure, or
characteristic in connection with other ones of the embodiments.

[0079]Although embodiments of the present invention have been described
with reference to a number of illustrative embodiments thereof, it should
be understood that numerous other modifications and embodiments can be
devised by those skilled in the art that will fall within the spirit and
scope of the principles of this invention. More particularly, reasonable
variations and modifications are possible in the component parts and/or
arrangements of the subject combination arrangement within the scope of
the foregoing disclosure, the drawings and the appended claims without
departing from the spirit of the invention. In addition to variations and
modifications in the component parts and/or arrangements, alternative
uses will also be apparent to those skilled in the art.